There's another reason the girls get makeup - it makes THEM feel better about THEMSELVES. This goes for pros and amateurs alike. For pros, it's part of their image and ritual to get in the zone. Many of them show up on some set at 9 am, coffee in hand, terrible attitude. After an hour in makeup and hair (and the makeup artist can have a tremendous impact, not just with her skills but with how she relates and talks to the girls, too) and our Oscar the Grouch has turned into the energetic, sexy, gorgeous queen you see on screen.
We do mostly amateurs and first timers and a lot of the girls are nervous. About being on camera for the first time, about the guy, about...well, everything. Girls are self-conscious as it is but now add the premise of 3+ cameras on them the entire time, plus whatever horror stories they make up in their heads. A girl can't relax and enjoy herself when she constantly thinks of those zits on her face, or how her eyes might look sunken in on camera because that's how she looks when she takes selfies of herself without makeup. So makeup and hair can take away a lot of these fears. Even just letting the girls do their own makeup and hair makes all the difference in the world. We like to tell girls to just do whatever they do when they go out for the night and want to look their best. Nothing more, nothing less. We want them to be themselves, but at their best. And, most importantly, that's what THE GIRLS want, too. This works wonders on attitudes and enthusiasm.